Lubricating oil compositions containing alkenyl succinimides of tetraethylene pentamine



United States Patent LUBRICATING GIL COMPOSITIONS CONTAENING ALKENYLSUCCINIMIDES 0F TETRAETHYL- ENE PENTAMINE Frank A. Stuart, Oriuda,Robert G. Anderson, Novato, and Alan Y. Drumrnond, Richmond, Calitl,assignors to Chevron Research Company, a corporation of Delaware NoDrawing. Filed Aug. 24, 1959, Ser. No. 835,437

6 Claims. (Cl. 252-515) This invention pertains to lubricating oilcompositions having incorporated therein metal-free detergents. Theseparticular metal-free detergents are N-substituted polyamine alkenylsuccinimides.

Alkenyl succinic anhydrides and numerous derivatives thereof are wellknown in the art. For example, alkenyl succinic anhydrides in which thealkenyl radical contains from to 20 carbon atoms are taught as corrosioninhibitors in lubricating oil compositions. Also, products obtained byreacting such alkenyl succinic acid anhydrides with monoamines aretaught as ferrous corrosion inhibitors for lubricating oil compositions.

However, the above known alkenyl succinimides are not useful asdetergents in lubricating oil compositions. In contrast thereto, theN-substituted polyamine alkenyl succinimides which are described hereinare new compounds which are useful as detergents in lubricating oilcompositions.

Present day internal combustion engines operate at high speeds and highcompression ratios. When used in the so-called city stop-and-go driving,which includes the greater part of the driving condition for a largepercentage of todays automobiles, the internal combustion engines do notreach the most efficient operating temperature. Under city drivingconditions, large amounts of partial oxidation products are formed, andreach the crankcase of the engine by blowing past the piston rings. Mostof these partial oxidation products are oil insoluble, tending to formdeposits on the various operating parts of the engine, such as thepistons, piston rings, etc. For the purpose of preventing the depositionof these products on the various engine parts, it is necessary toincorporate detergents in the lubricating oil compositions, thus keepingthese polymeric products highly dispersed in a condition unfavorable fordeposition on metals.

For the most part, the various detergents which are added to crankcaseoils to reduce this formation of sludges and varnishes are metal organiccompounds, particularly those compounds wherein the metal is linked toan or ganic group through an oxygen atom. Although thesemetal-containing organic compounds have some etfectiveness as detergentsfor dispersing the precursors of deposits within the oil itself ratherthan permitting Patented Jan. 2, 1968 lubricating oil compositions whichare compounded with a metal-free detergent.

Therefore, in accordance with this invention, it has been discoveredthat lubricating oil compositions particularly useful for heavy dutyservice are obtained by incorporating N-substituted monoalkenylsuccini-rnides derived from tetraethylene pentamine in oils oflubricating viscosity.

By the use of lubricating oil compositions containing the N-substitutedalkenyl succinimides described herein, diesel and gasoline engine partsremain remarkably free of deposits and varnish, even under severeoperating conditions.

These new compounds, which are monoalkenyl succinimides of tetraethylenepentamine, have the formula:

wherein R is a hydrocarbon radical having a molecular Weight from about400 to about 3000; that is, R is a hydrocarbon radical containing about30 to about 200 carbon atoms.

These alkenyl succinimides of tetraethylene pentamine can be prepared byreacting maleic anhydride with an olefinic hydrocarbon, followed byreacting the resulting alkenyl succinic anhydride with tetraethylenepentamine. The R radical of the above formula, that is, the alkenylradical, is derived from an olefin containing from 2 to 5 carbon atoms.Thus, the alkenyl radical is obtained by polymerizing an olefincontaining from 2 to 5 carbon atoms to form a hydrocarbon having amolecular weight ranging from about 400 to about 3000, more preferably,900 to 1200. Such olefins are exemplified by ethylene, propylene,l-butene, Z-butene, isobutene, and mixtures thereof. Since the methodsof polymerizing the olefins to form polymers thereof is immaterial inthe formation of the new compound described herein, any of the numerousprocesses available can be used therefor.

The preparation of N-substituted monoalkenyl succinimides derived fromtetraethylene pentamine can be described generally by the followingequations, using a polymer of isobutene as an example of the alkenylradical: I 0

them to form added deposits on the engine parts, I they have thedisadvantage of forming ash deposits in the C 3 engine. These ashdeposits lower engine performance by CH:C fouling plugs and valves, andcontributing to preignition. 11

CH3 CH3 CH3 0 l I CH3CCH2-OH?' CH=CCH2OHC\ GEM-CH2 CHa n /O NH:C2H4N /NH011 -0 CH2-CH2 CH3 CH3 CH 0 I I GHaCCHz-CHCIJ OH=CCHCHC\ CHPCHQ CH3 /n/NCH2CH2N /NH CHz-O CHa-CH:

It is a particular object of this invention to provide wherein n has avalue of about 7 to about 50.

The above reaction between a polyolefin and maleic anhydride is anuncatalyzed addition reaction which should not be confused with acopolymerization reaction such as that obtained with a vinyl monomer andmaleic anhydride. While the general reaction of an olefin and maleicanhydride is well known for olefins of low molecular weight (e.g.,olefins of 18 carbon atoms), no previous work has been done with maleicanhydride and the high molecular weight olefins as described herein.

The reaction set forth and described by Equation I hereinabove canproceed in a mol ratio of the polyolefin to the maleic anhydride of 1:1to 1:10, preferably from 1:1 to 1:5. The reaction temperature can varyfrom 300 F. to 450 F. Because of the greater yield of products obtainedthereby, it is preferred to use the high range of temperatures (e.g.,375 F. to 450 F.). In the second step of the reaction as exemplified byEquation II hereinabove, the yield of the imide is extremely high eventhough the reactants are used in equal molar ratios. This is surprising,since under the conditions of the reaction there is an excess ofsecondary amino groups over primary amino groups, and any reaction withthe secondary amino groups would lead to amide formation; thus,preventing imide formation.

The reaction described by Equation 11 hereinabove can be made at 220 F.to 500 F., preferably from 300 F. to 400 F. The alkenyl succinicanhydride and the tetraethylene pentamine are reacted in about equalmolar quantities.

Since the reaction between the polyolefin and maleic anhydride may notgo to completion, the resulting alkenyl succinic anhydride may containsome unreacted polyolefin. As it may not be desirable to separate outthis unreacted polyolefin at this stage, the resulting imide formed byreaction of the alkenyl succinic anhydride and the diamine will containthis polyolefin as an impurity which can be a diluent in the formationof lubricating oil compositions. However, if it is so desired, thisunreacted polyolefin can be removed by precipitation, for example, byacetone or methanol from a hydrocarbon solution.

Lubricating oils which can be used as base oils include a wide varietyof lubricating oils, such as naphthenic base, paraflin base, and mixedbase lubricating oils, other hydrocarbon lubricants, e.-g., lubricatingoils derived from coal products, and synthetic oils, e.g., alkylenepolymers (such as polymers of propylene) butylene, etc., and themixtures thereof), alkylene oxide-type polymers (e.g., propylene oxidepolymers) and derivatives, including alkylene oxide polymers prepared bypolymerizing the alkylene oxide in the presence of water or alcohols,e.g., ethyl alcohol, dicarboxylic acid esters (such as those which areprepared by esterifying such dicarboxylic acids as adipic acid, azelaicacid, suben'c acid, sebacic acid, salkanol succinic acid, fumaric acid,maleic acid, etc., with alohols such as butyl alcohol, hexyl alcohol,2-ethyl hexyl alcohol, dodecyl alcohol, etc.), liquid esters of acids ofphosphorus, alkyl benzenes (e.g., monoalkyl benzene such as dodecylbenzene, tetradecyl benzene, etc., and dialkyl benzenes (e.g., n-nonylZ-ethyl hexyl benzene); polyphenyls (e.g., biphenyls and terphenyls),alkyl biphenyl ethers, polymers of silicon (e.g., tetraethyl silicate,tetraisopropyl silicates, tetra(4-methyl-2-tetraethyl) silicate, hexyl(4-methyl-2-pentoxy) disiloxane, poly(methyl) siloxane,poly(methylphenyl) siloxane, etc. Synthetic oils of the alkyleneoxide-type polymers which may be used include those exemplified by thealkylene oxide polymers.

The above base oils may be used individually or in combinations thereof,wherever miscible or wherever made so by the use of mutual solvents.

The alkenyl succinimides of tetraalkylene pentamine can be used in oilsof lubricating viscosity in amounts of 0.1% to 80%, by weight,preferably 0.25% to 5%, by weight.

The preparation of the alkenyl succinimides of tetraalkylene pent-amineis illustrated in the following examples.

Example I.-Preparati0n 0f polybutenyl succinic anhydride A mixture of1000 grams (1 mol) of polybutene having a molecular weight of about 1000and 98 grams (1 mol) of maleic anhydride was heated at 410 F. in anitrogen atmosphere with agitation for a period of 24 hours. Thereaction mixture was cooled to 150 F. and 700 cc. of hexane added; afterwhich the mixture was filtered under vacuum. After vacuum distillationto remove the hexane from the filtrate, the product was maintained at350 F. at an absolute pressure of 10 mm. Hg for one hour to removetraces of maleic anhydride. The crude polybutenyl succinic anhydridethus prepared had a saponification number of 79.

Example I1.Preparati0n of tetraethylenepentamine derivative 0 thepolybutenyl succinic anhydride of Example l hereinabove A mixture of 84grams (0.45 mol) of tetraethylene pentamine and 702 grams (0.45 mol) ofthe polybutenyl succinic anhydride of Example I hereinabove, was blendedwith agitation at 125 F. in a nitrogen atmosphere. The temperature wasincreased to 400 F. during a period of one hour, after which theabsolute pressure was reduced to about 200 mm. Hg during a period of 30minutes to facilitate the removal of water. The reaction mixture wasthen allowed to reach room temperature at this reduced pressure. Thereaction product contained 5.1% nitrogen (theory=5.4%). Infra-redanalysis showed that the reaction product was an imide containing apolybutene side chain.

As detergents for lubricating oil compositions, the compounds of thisinvention are more efiective than alkenyl succinimides having fewernitrogen atoms in the amine portion of the molecule, and succinimideshaving less than 30 carbon atoms in the alkenyl radical. The use of amylamine, for example, in place of tetraethylene pentamine in thepreparation of the succinimide, results in a product which isineffective as a detergent in lubricating oil compositions.

Table I hereinbelow presents data obtained with lubricating oilcompositions containing N-substituted monoalkenyl succinimides derivedfrom tetraethylene pentamine.

The monoalkenyl succinimide used was an N-substituted succinimidederived from tetraethylene pentamine Wherein the alkenyl radical had amolecular weight of about 1000, which alkenyl radical was a polymer ofisobutene.

The tests were made in a Caterpillar L-l engine according to SupplementI conditions for a period of 120 hours as described in the CoordinatingResearch Council Handbook, January, 1946.

The PD Nos. refer to the piston discoloration rating. After the enginetest, the three piston lands are examined visually. To a piston skirtwhich is completely black is assigned a PD number of 800; to one whichis completely clean, a PD number of 0; to those intermediate betweencompletely black and completely clean are assigned PD numbersintermediate in proportion to the extent and degree of darkening.

The G.D. Nos. refer to the percentage deposits in the piston ringgrooves; and 0 evaluation being a clean groove; and a number of 100being a groove full of deposits.

The base oils were California SAE 30 base oils.

The dithiophosphate was a zinc salt of a mixed dialkyl dithiophosphatewherein one of the alkyl radicals contained 4 carbon atoms and the otheralkyl radical contained 5 carbon atoms. The dithiophosphate was presentin the lubricating oil compositions in an amount of 18 millimols perkilogram (Le, 18 mm./kg.) of finished product, based on the metalcontent.

TABLE I A I B o D Additive:

Succiniuu'de, Wt. percent- 0.0 3. 2. 0 Dithiophosphate:

(1) ImJkg 0.0 0.0 18 18 (2) MIn./kg 0.0 0.0 Test Results:

G.D. No 2 39 4 21 1 P.D. N0 2 800, 800, 800 0, 0, O 600, 300, 200 40, 1,5

1 An alkenyl succinimide of tetraethylene pentamine wherein the allrenylradical has had a molecular weight of approximately 1,000, which alkenylradical was a polymer of isooutene 2 These test results were obtained ina Caterpillar L-l test under the MIL-D2104 conditions. Thus, under themore severe supplement-l conditions, these G.D. N as. would beconsiderably higher.

The marked synergistic efiect obtained by the combina- T ABLE 1H tron ofthe N-substituted alkenyl succinimides of this invention and thedithiophosphates is particularly noted. I I l I K i L Table IIhereinbelow presents data obtained in an FL-2 ti 0 Additive: test, usmga 6 cylinder Chevrolet engine Opera 11,, fiat succinimide, Wt percent3'0 3'0 3' 0 3 0 2500 r.p.m for a period of 40 hours, which test is in yDithiopl1osphate,mm./kg 1s 18 18 18 described in a Coordmatmg ResearchCouncil. bulletm Test Results! -t it th Duration of Test (hours) 20 3652 72 tled Research Technique for the Determination of e gearing Weight133 133 206 240 Efiects of Fuels and Lubricants on the Formation of De-Plston Varnish Refine posits During Moderate Temperature Operation.(1948).

The piston varnish rating is a visual observation of the amount ofvarnish on a piston skirt, with 10 being the maximum rating for aperfectly clean piston and a 0 being the rating of a piston fullycovered with black varnish. This piston varnish rating correlates withroad performance in automobiles.

The total rating is the overall deposit rating of the engine. The ratingvalues range from 0, the poorest value, to 100, the top value. Thesefigures indicate the percentage rating for the engine.

The base oil was an SAE base oil.

The succinimide and the dithiophosphate were the same as those describedfor Table I hereinabove.

It is readily seen from the data set forth hereinabove in Tables I andII that lubricating oil compositions containing the alkenyl succinimidesof tetraethylene pentamine as described herein are superior aslubricating oil compositions for the lubricating of internal combustionengines.

Table 111 hereinbelow presents data obtained with lubricating oilcompositions under L-4 test conditions. This L-4 engine test which isfully described in the CRC Handbook, 1946 edition, Coordinating ResearchCouncil, New York, New York, is designed to evaluate the bearingcorrosion characteristics and high temperature detergency of lubricatingoil compositions. The detergency characteristics are rated by the pistonvarnish rating on the same scale described above for the FL-2 test. TheL-4 test was continued beyond the normal 36 hours. The number of hoursis the hours at which the same specimens were evaluated then placed inthe engine for further testing.

The dithiophosphate was a zinc salt of a dialkyl dithiophosphate whereinone of the alkyl radicals contained 4 carbon atoms and the other alkylradical contained 5 carbon atoms.

The succinimide and the dithiophosphate were the same as those describedhereinabove.

This performance is exceptionally good.

As is known, the use of a number of polymeric ashless detergents and V1.improvers in lubricating oil compositions results in the formation oflead deposits on many of the parts of gasoline engines. These depositsresult from the lead halides formed from the tetraethyl lead and thescavengers used in commercial gasolines. Engine failures result from theformation of these deposits. As shown by the data of Table Ihereinbelow, the addition of the N-substituted alkenyl succinimides ofthis invention markedly improves the performance of such oils.

These tests, which correlate with actual road performance, were made ina 6-cylinder Chevrolet engine run at 2500 r.p.m., with 50 brakehorsepower, an oil sump temperature of F. for a period of 36 hours,using a commercial gasoline containing 3 cc. of TEL per gallon. The oilwas changed after 24 hours.

The lead rating scale ranges from 10 for a clean engine, to zero for anengine containing heavy lead deposits. Similarly, in the same enginetest, piston varnish ratings were obtained, a value of 10 for a cleanpiston, and a value of zero for a piston heavy with varnish.

The succinimide and the dithiophosphate were the same as that describedin the tables hereinabove.

TABLE IV Additive: M Succinimide, weight percent 2 Dithiophosphate,mm./kg. 18 Test results:

Lead rating 9.4 Piston varnish rating 9.9 Total rating 99.1

In addition to the dithiophosphate described hereinabove, lubricatingoil compositions containing the N-substituted alkenyl succinimides oftetraethylene pentamine of this invention may also contain otherdetergents, viscosity index improving agents, rust inhibitors, oilinessagents, grease thickening agents, etc.

We claim:

1. A lubricating oil composition comprising a major proportion of an oilof lubricating viscosity, and in an amount suficient to impartdetergency characteristics thereto, a monoalkenyl succinimide of theformula:

7 wherein R is a hydrocarbon radical having a molecular weight of fromabout 900 to about 3000.

2. A lubricating oil composition consisting essentially of an oil oflubricating viscosity, and from about 0.1% to about 80%, by weight, of amonoalkenyl succinirnide of tetraethylene pentamine of the formula:

RGHi| J lTICH2CHz(NHCH2CH2)s-NH GHzC=-O wherein R is a hydrocarbonradical derived from a polymer of an olefin containing from 2 to carbonatoms, said polymer having a molecular weight in the range of about 900to about 3000.

3. A lubricating oil composition consisting essentially of an oil oflubricating viscosity, and from about 0.1% to about 80%, by weight, of amonoalkenyl succinirnide of tetraethylene pentamine of the formula:

i RCH(3 NGHzCHz(NHCHzCHg)g-NH1 CH2C=O wherein R is a a hydrocarbonradical derived from a polymer of an olefin containing from 2 to 5carbon atoms, said polymer having a molecular weight in the range ofabout 900 to about 1200.

wherein R is a polymer of isobutene having a molecular Weight of about1000.

5. A lubricating oil composition comprising a major proportion of apetroleum lubricating oil, and from about 0.25% to about 5%, by weight,of an N-substituted monoalkenyl succinimide of the formula:

in which structural formula R is a substantially aliphatic hydrocarbonradical of from to 200 carbon atoms, with an equal molar quantity oftetraethylene pentamine at a temperature in the range of 220 to 360 F.

References Cited UNITED STATES PATENTS 2,490,744 12/ 1949 Trigg et a1252-392 X 2,604,451 7/ 1952 Rocchini 252-515 2,638,450 5/1953 White eta1. 252-515 DANIEL E. WYMAN, Primary Examiner.

PATRICK P. GARVIN, JULIUS GREENWALD,

Examiners.

G. O. ENOCKSON, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,361,673 January 2, 1968 Frank A. Stuart et a1.

It is certified that error appears in the above identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 1, line 57, "plugs" should read spark plugs Columns 1 and 2,formula II should appear as shown below:

iIH (II-I (fH /O CHgC-CH CH- -C CH=C-CH -CH:C I

CH n /O H NCH CH (NHCH CH -NH CH CH CH O 3 3 3 CH -C-CH CH -IC CH=C-CHCH CH n /NCH CH (NHCH CH -NH CH --C Column 3, line 46, (such as polymersof propylene)" should read (such as polymers of propylene, Column 4,line 6, "of polybutene" should read of a polybutene Column 6, line. 35,"I"-should read IV same column 6, lines 69 to 75, the

formula should appear as shown below:

Signed and sealed this 16th day of December 1969.

(SEAL) Attest:

Attesting Officer Commissioner of Patents

